The present invention generally relates to toilets and, more particularly, to vacuum toilet systems.
Vacuum toilet systems are generally known in the art for use in both vehicle and stationary applications. A vacuum toilet system typically comprises a bowl for receiving waste having an outlet connected to a vacuum sewer line. A discharge valve is disposed between the bowl outlet and vacuum sewer line to selectively establish fluid communication therebetween. The vacuum sewer line is connected to a collection tank that is placed under partial vacuum pressure by a vacuum source, such as a vacuum blower. When the discharge valve is opened, material in the bowl is transported to the sewer pipe as a result of the pressure difference between the interior of the bowl and the interior of the sewer line. Conventional vacuum toilet systems also include a source of rinse fluid and a rinse fluid valve for controlling introduction of rinse fluid into the bowl.
Conventional discharge valves are overly complicated to assemble. Such valves typically have a movable valve member linked to an actuator that operates the valve member between open and closed positions. The linkage between the valve member and the actuator often includes pivoting arms, joints, and other components which increase the complexity of valve assembly. In addition, gearing is often needed to slow the actuator speed to the desired valve actuation speed. Gear heads having four or more stages are often required to obtain the desired speed. Each stage, however, introduces friction and other losses that decrease the efficiency of power transmission from the actuator to the valve member.
In addition, conventional discharge valves undesirably generate a high noise level during a flush operation. When the discharge valve opens in response to a flush command, a significant amount of air, in addition to waste material and rinse fluid, is pulled into the sewer line. The air flows through a relatively narrow bowl outlet, which creates the noise. The noise may further be amplified by the shape of the toilet bowl. Apparatus is known for reducing the noise by introducing a secondary source of air into the sewer pipe during a flush cycle. This apparatus, however, requires a separate valve and actuator, thereby increasing the cost and complexity of the toilet.
Still further, vacuum toilet systems in general and discharge valves in particular are overly difficult and time consuming to maintain. Maintenance concerns are particularly significant in aircraft applications, in which a number of sub-systems are installed on board. According to general practice in the airline industry, each sub-system includes one or more components which must be replaced in the event of failure, such replacement components being commonly referred to as line replaceable units (LRUs). Presently, the entire vacuum toilet is defined as the LRU for the vacuum toilet system. As a result, an airline must stock one or more replacement toilets in the event of a toilet failure, so that the replacement toilet may be swapped in for the faulty toilet. A xe2x80x9cbench testxe2x80x9d is then performed on the faulty toilet to determine which components have failed in the toilet. The faulty components are then repaired or replaced (which may include significant disassembly and reassembly of the toilet) so that the repaired toilet may be reused on another aircraft.
Each of the steps performed during a toilet repair is overly difficult and time consuming. To remove an entire toilet assembly from an aircraft requires disassembly of at least four self-locking mounting fasteners, an electrical connection, a grounding strap, a potable water line connection, and a waste discharge pipe connection. Each connection may be difficult to access, and may require a particular tool in order to loosen and disconnect. The same connections must then be reconnected for the replacement toilet.
Even if it were possible to remove and replace a single toilet component, it would be overly difficult and time consuming to do so. Removal of a component would require disconnection of several wires and pipes, and the components are often located in areas which are difficult to access. Furthermore, it would be difficult to diagnose whether one component or several components had failed. There exists a multitude of combinations of simultaneous component failures, which may lead to trouble-shooting errors and the replacement or repair of non-faulty components.
Conventional discharge valves also use seals which are difficult to install and replace. As noted above, a discharge valve typically has a moving valve member disposed inside a housing. Seals are typically provided inside the housing to prevent leaks between the valve member and the upstream and downstream sides of the housing. As a result, the valve housing must be disassembled to remove and replace a faulty seal.
Conventional vacuum toilets further fail to provide adequate feedback regarding valve position. Conventional discharge valves are typically driven by an electric motor actuator having mechanical limit switches and signal switches to control valve position. Such a switch is overly complicated to use and maintain. The switches must be precisely set to trigger at the appropriate time, and special tooling is often required to set the switch. In addition, by locating the switches in the actuator, they are subject to mechanical wear and contact erosion, which may alter the setting of the switch, thereby requiring re-setting. Furthermore, lubricant or other materials may migrate to the switches, causing switch failure. Most importantly, the conventional apparatus is unreliable since valve position is inferred from the actuator position. As a result, the conventional approach is not responsive to various failure situations where the actuator may be operable but the valve is not, such as when the linkage connecting the actuator to the valve is broken or defective.
In accordance with certain aspects of the present invention, a discharge valve is provided for use in a vacuum toilet system having a waste receptacle defining an outlet and a sewer line placeable under partial vacuum. The discharge valve comprises a housing defining an inlet and an outlet, and a rotatable discharge valve member disposed in the housing for selectively establishing fluid communication between the inlet and the outlet, wherein a periphery of the valve member being formed with a series of gear teeth. An actuator has a rotatable gear adapted to engage the periphery of the discharge valve member.
In accordance with additional aspects of the present invention, a discharge valve is provided for use with a vacuum toilet system having a waste receptacle defining an outlet and a sewer line placeable under partial vacuum. The discharge valve comprises a housing defining a flush valve inlet fluidly communicating with the waste receptacle outlet, a flush valve outlet fluidly communicating with the sewer line, an air intake valve inlet fluidly communicating with ambient air, and an air intake valve outlet fluidly communicating with the sewer line. A movable valve member is disposed in the housing and defining first and second apertures, the valve member having a closed position in which the valve member obstructs fluid communication between the flush inlet and flush outlet, and between the air intake valve inlet and air intake valve outlet, and an open position in which the first and second apertures establish fluid communication between the flush inlet and flush outlet, and between the air intake valve inlet and air intake valve outlet.
In accordance with further aspects of the present invention, a discharge valve provided for use with a vacuum toilet system having a waste receptacle defining an outlet and a sewer line placeable under partial vacuum. The discharge valve comprises a housing defining a flush valve inlet fluidly communicating with the waste receptacle outlet and a flush valve outlet fluidly communicating with the sewer line. A rotatable valve member is disposed in the housing and defines a first aperture. The valve member has a closed position in which the valve member obstructs fluid communication between the flush valve inlet and the flush valve outlet, and an open position in which the first aperture establishes fluid communication between the flush valve inlet and flush valve outlet. A first seal is provided having a cylindrical wall sized for insertion from an exterior of the housing into the flush valve inlet, the cylindrical wall having a bottom edge adapted to engage and seal with the rotatable valve member.
In accordance with still further aspects of the present invention, a discharge valve is provided for use in a vacuum toilet system. The discharge valve comprises a housing defining a discharge valve inlet and a discharge valve outlet. A valve member is disposed inside the housing, the valve member being movable between a closed position in which the valve member obstructs fluid communication between the discharge valve inlet and the discharge valve outlet, and an open position in which fluid communication is established between the discharge valve inlet and the discharge valve outlet. A sensor is provided for detecting position of the valve member, the sensor being located outside of the housing.
In accordance with yet additional aspects of the present invention, a discharge valve is provided for use in a vacuum toilet system having a bowl defining an outlet and a sewer line placeable under partial vacuum. The discharge valve comprises a housing defining a discharge valve inlet adapted for fluid communication with the bowl outlet and a discharge valve outlet adapted for fluid communication with the sewer line. A seal is disposed inside the discharge valve outlet, and a disk is disposed inside the housing and has first and second apertures connected by a slot. The first aperture, second aperture, and slot divide the disk into first and second disk halves, and the disk is rotatable between a closed position, in which one of the first and second disk halves engages the seal to obstruct fluid flow, and an open position, in which one of the first and second apertures is aligned with the seal to allow fluid flow therethrough. The slot allows the first and second disk halves to deflect in response to partial vacuum at the discharge valve outlet to more reliably engage the disk with the seal in the closed position.